Stable dentifrice containing neutral siliceous polishing agent

ABSTRACT

There is disclosed a dentifrice formulation which is stable in the sense of not producing gassing as evidenced by visually discernable distention over a period of 168 days at 43° C. in an unlined aluminium tube. 
     The formulation comprises an aqueous dentally acceptable oral vehicle at least 27.5% by weight of the dentifrice comprising water and dispersed in the said oral vehicle from 10 to 40% by weight of the dentifrice of a neutral siliceous polishing agent having a stirred slurry pH (as herein defined) in the range from 6.5 to 7.5, and a stabilizing amount of monofluorophosphate ion, the dentifrice having a stirred slurry pH in the range from 5.5 to 8.

This invention relates to a stable dentifrice and in particular to adentifrice which can be used in an unlined aluminium tube.

According to the present invention a stable dentifrice comprises anaqueous dentally acceptable oral vehicle, at least 27.5% and typically30 to 60%, preferably 40 to 55% for example about 45% by weight of thedentifrice comprising water and dispersed in the said oral vehicle from10 to 40%, preferably 10 to 30% and especially 15 to 25% by weight ofthe dentifrice of a neutral siliceous e.g. alkali metal aluminosilicate,polishing agent characterised as having a stirred slurry ph (as definedherein) in the range from 6.5 to 7.5, preferably 6.7 to 7.3 and astablizing amount of mono-fluorophosphate ion, the dentifrice having astirred slurry pH in the range 5.5 to 8, preferably 6.5 to 7.5, andespecially 6.7 to 7.3, optionally a non-toxic amount of at least 0.2% byweight of the dentifrice of chloroform, and desirably, at least whenchloroform is present, from 0.05 to 5 % by weight of the dentifrice of astabilizing anionic phosphate ester mixture, the said mixture comprisingmonoester of the formula: ##STR1## and diester of the formula: ##STR2##wherein R is an alkyl group of 10 to 20 carbon atoms; n is a number from1 to 6; and M is hydrogen, alkali metal or ammonium. The stabilizinganionic phosphate ester mixture reduces or prevents corrosion in thepresence of chloroform and stabilises the dentifrice.

It is an advantage of this invention that a stable dentifrice containingsiliceous polishing agent is provided.

The stability with which the present invention is concerned is thesubstantial absence of gas generating reactions between the componentsof the dentifrice and the aluminium surface of an unlined aluminium tubeas shown by the absence of visually discernable distension of the closedtoothpaste tube containing the dentifrice when the said tube has beenheld at 43° C. for 168 days.

The invention also extends to an unlined aluminium tube filled with astable dentifrice in accordance with the present invention.

The stabilizing mono-fluorophophosphate ion may be provided by anyappropriate compound thereof but a particularly convenient compound issodium monofluorophosphate.

This may be used in any amount having the necessary defined stabilizingeffect on the particular embodiment of the dentifrice according to theinvention but amounts providing at least 0.01% mono-fluorophosphate ionare prudently used and for greater certainty at least 0.05% or at least0.075, or 0.09%, should be used. Sodium monofluorophosphate will providesuch amounts of the monofluorophosphate ion when present in amounts of0.076, 0.38, 0.57, or 0.68% respectively. Use of 0.7 to 0.8% of sodiummonofluorophosphate has been found particularly effective and thus apreferred proportion thereof is at least 0.7%. Higher amounts are notprecluded but an upper limit of 7.6% will usually not be exceeded.

The polishing material employed in the present invention is neutralsiliceous material which may contain a small amount e.g. up to about 10%or somewhat more of alumina interbonded in the silica lattice. It can befurther characterised as being synthetic and amorphous and as having arefractive index between about 1.4 and 1.5.

If desired, other polishing agents which as individual components do notcontribute substantially to instability or corrosivity with an unlinedaluminium surface may also be present. Such additional polishing agentsinclude dicalcium phosphate dihydrate and anhydrous dicalcium phosphateas well as tricalcium phosphate, calcium pyrophosphate and calcinedalumina. When an additional polishing agent is present, the amount ofpolishing material in the dentifrice may amount to up to about 75% byweight preferably 30 to 55% of the dentifrice.

When chloroform is present in the formulation it is employed in anon-toxic amount which is effective to provide flavour to thedentifrice. However since chloroform in combination with the siliceouspolishing agent results in instability and corrosion in the presence ofan unlined aluminium surface an appropriate stabilizing amount of ananionic phosphate ester mixture is also incorporated in such chloroformcontaining formulations. The chloroform may be present in an amount aslow as about 0.2% by weight of the dentifrice and as high as 8% byweight of the dentifrice and as high as 8% by weight or more. An amountof chloroform in the range of 0.5 to 3.5% by weight is preferred. It isnoted that in view of the toxic properties of large amounts ofchloroform some countries have or are establishing legal limits on themaximum amount of chloroform which can be used in products such asdentifrices, providing a safety margin by not approaching the toxicthreshold too closely. However, even given such legal maxima, the effectof the stabilizing phosphate ester can be observed when non-toxicamounts such as 8%, 5%, 3.5%, 0.5% or 0.2% by weight of chloroform arepresent.

The anionic phosphate esters are mixtures of mono and di-esters of theformulas set forth above. Suitable esters are available from MoDo KemiAktiebolaget, formerly Berol Aktiebolaget, of Sweden under the nameBEROL (BEROL is a trade mark) and may include an anionic triester moietytoo, as well as some non-ionic portion. BEROL 729 has alkyl chainlengths of 16 to 18 carbon atoms and contains series of 4 ethylene oxideunits. BEROL 729 is generally used in neutralised or partiallyneutralised form.

Further anionic phosphate esteres which may be used in acid orneutralised forms are BEROL 525 which contains alkyl groups of 10 to 18carbon atoms and series of 5 ethylene oxide units and BEROL 513 whichalso contains alkyl groups of 16 to 18 carbon atoms. However, BEROL 525,is also preferred in neutralised or partially neutralised form. FurtherBEROL anionic phosphate esters are available as BEROL 521, BEROL 724 andBEROL 733. The weight ratio of monoester to diester may vary, typicallyfrom about 1:10 to 10:1.

When the acid forms of the anionic phosphate ester surface active agentsare neutralised or partially neutralised, alkali metal, preferablysodium, or ammonium cations are present.

Desirably the stirred slurry pH of the completed dentifrice is in therange from 6.5 to 8, preferably 6.5 to 7.5. If appropriate, the pH maybe adjusted, for instance with phosphoric acid.

The preferred anionic phosphate ester is BEROL 513.

The anionic phosphate ester, when present, is used in an amount up toabout 5% by weight effective to stabilize the dentifrice in an unlinedaluminium tube. This amount can be as little as about 0.05% and woulddepend, at least in part on the amounts of chloroform and siliceouspolishing agent present. For instance with about 3.5% chloroform, itwould be desirable to employ about 1.5% of the anionic phosphate ester.A typical ester content would be in the range of 0.1 to 2% by weight,preferably 0.5 to 1.5%, of the dentifrice.

Besides stabilizing the dentifrice the anionic phosphate ester alsoprovides surface active properties. Such surface active properties aredescribed in British Patent Specifications Nos. 1475251 and 1475252.

The dentifrice as mentioned above contains a high proportion of a liquidvehicle which may comprise water, in amount of at least 27.5% by weightof the preparation. The liquid vehicle may additionally comprisehumectants such as glycerine, but unlike conventional high liquidvehicle dentifrices can dispense with such humectants as sorbitolsolution or propylene glycol. A mixture of water and glycerine isparticularly advantageous.

The solid portion of the vehicle of the dentifrice is a gelling agent orbinder such as hydroxyethyl cellulose or hydroxypropyl cellulose, Irishmoss, gum tragacanth, sodium carboxymethyl cellulose, polyvinylpyrrolidone, xanthan, starch or water-soluble hydrophilic colloidalcarboxyvinyl polymers such as those sold as CARBOPOL 934 and 940(CARBOPOL is a trade mark).

The dentifrices will include an organic surface active agent which canbe replaced by the anionic phosphate ester stabilizing agent if such ispresent, or retained. Such additional agent may be anionic, nonionic,cationic or ampholytic in nature, and it is preferred to employ as thesurface active agent a detersive material which imparts to thedentifrice detersive and foaming properties. Suitable types of suchdetergents are water-soluble salts of higher (i.e. having at least 12carbon atoms) fatty acid monoglyceride monosulphates, such as the sodiumsalt of the monosulphated monoglyceride of hydrogenated coconut oilfatty acids, higher alkyl sulphates, such as sodium lauryl sulphate,alkyl aryl sulphonates, such as sodium dodecyl benzene sulphonate,olefin sulphonates, such as a sodium olefin sulphonate in which theolefin group contains 12-21 carbon atoms, higher alkyl sulphoacetates,higher fatty acid esters of 1,2-dihydroxy propane sulphonates, and thesubstantially saturated higher aliphatic acyl amides of lower (i.e.having not more than 4 carbon atoms) aliphatic amino carboxylic acidcompounds, such as those having 12 to 16 carbons in the fatty acid,alkyl or acyl radicals. Examples of the last mentioned amides areN-lauroyl sarcosine, and the sodium, potassium and ethanolamine salts ofN-lauroyl, N-myristoyl or N-palmitoyl sarcosine, which should besubstantially free from soap or similar higher fatty acid material whichtends to substantially reduce the effect of these compounds. The use ofthese sarcosine compounds in dentifrices is particularly advantageoussince these materials exhibit a prolonged and marked effect in theinhibition of acid formation in the oral cavity due to the carbohydratesbreakdown in addition to exerting some reduction in the solubility oftooth enamel in acid solutions.

Other particularly suitable surface-active materials include nonionicagents such as condensates of sorbitan monostearate with approximately60 moles of ethylene oxide, condensates of ethylene oxide with propyleneglycol ("Pluronics"-PLURONIC is a Trade Mark) and amphoteric agents suchas quaternised imidazole derivatives, which are available under thetrade mark MIRANOL such as MIRANOL C2M. Cationic surface activegermicides and anti-bacterial compounds such asdiisobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride, tertiaryamines having one fatty alkyl group (of from 12-18 carbon atoms) and two(poly) oxyethylene groups attached to the nitrogen (typically containinga total of from 20 to 50 ethanoxy groups per molecule) and salts thereofwith acids, and compounds of the structure ##STR3## wherein R is a fattyalkyl group typically containing from 12 to 18 carbon atoms, and x, yand z total 3 or higher, as well as salts thereof with mineral ororganic acids, may also be used.

The total amount of surface active agent, including the anionicphosphate ester, if present, typically does not exceed about 5%.

In certain forms of this invention, in addition to the source ofmono-fluorophosphate ion, a fluorine-providing compound is present inthe oral preparation. These compounds may be slightly soluble in wateror may be fully water-soluble. They are characterised by their abilityto release fluoride ions in water and by substantial freedom fromreaction with other compounds of the oral preparation. Among thesematerials are organic amine fluorides such as cetylamine hydrofluorideand bis (hydroxyethyl)-aminopropyl N-hydroxy-ethyl-octadecyl-aminedihydrofluoride or inorganic fluoride salts, such as suitable alkalimetal, alkaline earth metal, and heavy metal salts, for example, sodiumfluoride, potassium fluoride, ammonium fluoride, a copper fluoride, suchas cuprous fluoride, zinc fluoride, a tin fluoride such as stannousfluoride, or stannous chlorofluoride, sodium fluorosilicate, ammoniumfluorosilicate, sodium fluorozirconate, aluminium mono anddi-fluorophosphate, and fluorinated sodium calcium pyrophosphate. Alkalimetal and tin fluorides are preferred. A mixture of sodium fluoride andsodium monofluorphosphate is also highly desirable.

The amount of the fluorine-providing compound is dependent to someextent upon the type of compound, its solubility, and the type of oralpreparation, but it must be a non-toxic amount. It is considered that anamount of such compound which releases a maximum of 1% by weight offluoride ion, based on the weight of the preparation, is satisfactory.Any suitable minimum amount of such compound may be used, but it ispreferable to employ sufficient compound to release from 0.005% to 1%,most preferably about 0.1%, by weight of fluoride ion. Typically, in thecases of alkali metal fluoride and stannous fluoride, this component ispresent in an amount up to 2% by weight, based on the weight of thepreparation, and preferably in the range of from 0.05% to 1%.

Antibacterial agents may also be present, typically in an amount of0.01-5% by weight. Typical antibacterial agents include

N^(1`--)( 4-chlorobenzyl)--N⁵ --(2,4-dichlorobenzyl) biguanide;

p--chlorophenylbiguanide;

4--chlorobenzhydrylbiguanide;

4--chlorobenzhydrylguanylurea;

N--3-lauroxypropyl--N⁵ --p--chlorobenzylbiguanide;

1,6--di--p--chlorophenylbiguanidohexane; (chlorhexidine);

1,6--bis(2--ethylhexylbiguanido)hexane;

1--(lauryldimethylammonium)--8--(p-chlorobenzyldimethylammonium) octanedichloride;

5,6--dichloro--2--guanidinobenzimidazole;

N¹ --p--chlorophenyl--N⁵ --laurylbiguanide;

5--amino--1,3--bis (2--ethylhexyl)--5--methylhexahydro pyrimidine; andtheir non-toxic acid addition salts.

Various other materials may be incorporated in the oral preparations ofthis invention as adjuvants. Examples are colouring or whitening agents,preservatives, silicones, chlorophyll compounds, and ammoniated materialsuch as urea, diammonium phosphate, and mixtures thereof.

These adjuvants, where present, are incorporated in the preparations inamounts which do not substantially adversely affect the properties andcharacteristics desired. Whitening agents such as titanium dioxide orzinc oxide, typically in amount of 0.2 to 1% by weight provide aparticularly fine cosmetic appearance to the dentifrice.

The dentifrice will usually contain flavouring and/or sweeteningmaterial, in addition to any chloroform which may be employed. Examplesof suitable flavouring constitutents are flavouring oils, e.g. oils ofspearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus,marjoram, cinnamon, lemon and orange, and methylsalicylate. Suitablesweetening agents include sucrose, lactose, maltoses, sorbitol, sodiumcyclamate, perillartine and saccharin. Suitably flavour and sweeteningagents may together comprise from 0.01% to 5% or more of thepreparation.

The dentifrice is typically prepared by dispersing the polishingmaterial (and when chloroform is to be present the phosphate ester) inthe dental vehicle and other components, (except for the chloroform) andthen subjecting the mixture to deaeration after which any chloroformwhich is to be incorporated may be introduced in a closed vacuum system.

The dentifrice is then placed in an aluminium tube.

Due to the compositions stability to aluminium, the inner surface of thealuminium tube need not be provided with a lining and thus the tubes canbe unlined aluminium tubes.

However the stability of the composition is of benefit even when linedtubes are to be used because in this case gassing of such tubes in whichthe lining may be defective or damaged in use so as to expose thealuminium surface is avoided. Also the invention permits the use of itschloroform containing embodiments in tubes which although lined, uselinings which can be penetrated by chloroform or its breakdown products.

The invention may be put into practice in various ways and a number ofspecific embodiments will be described to illustrate the invention withreference to the accompanying Examples.

All amounts and proportions given in this specification are by weightunless otherwise indicated.

EXAMPLES 1 to 19

The following dentifrice formulations given in Tables 1A, 1B and 1Cbelow were prepared in conventional manner by mixing the ingredientstogether and allowing them to gel with the water for 15 minutes at 45°to 50° C. after which the gelled blend was mixed to adequately dispersethe powders.

Tables 1A to 1C give the composition and initial properties of thedentifrice formulations.

The pH measurement of solids as slurries may be liable to variationdepending on how the slurry is made up and we thus prefer to define thetechnique used for pH measurement herein.

The pH values both for the sodium alumino silicate (SAS) and thedentifrice formulations were measured on KENT Model No. 7060 pH meterusing an ORION combination electrode calibrated at pH 9.2±0.1 at 20° C.using British Drug Houses borate buffer and at pH 7.0±0.1 at 20° C.using BDH phosphate buffer.

A 20% aqueous slurry in distilled water of the test material was thenmade up and stirred for 10 minutes using a magnetic stirrer prior todetermination of the pH at 20 ° C. A pH measured this way will bereferred to herein as a stirred slurry pH.

The following points should be noted about the data in Tables 1A to 1C.

Note 1

The sodium carboxymethyl cellulose is grade 7 MF.

Note 2

The % soluble fluoride value given is the (average of two readings)×10₂, i.e. a figure of 10 in Table 1A to 1C means an average fluoridecontent of 0.10.

Note 3

The pH for the dentifrice was measured immediately after the dentifricehad been made up.

The dentifrice formulations given in Tables 1A to 1C are filled inconventional manner into unlined aluminium tubes.

                  TABLE 1A                                                        ______________________________________                                                 Example                                                              Component  1      2      3     4    5    6    7                               ______________________________________                                        Glycerine  25.00  25.00  25.00 25.00                                                                              25.00                                                                              25.00                                                                              25.00                           Sodium carboxy-                                                                          1.00   1.00   1.00  1.00 1.00 1.00 1.00                            methyl cellu-                                                                 lose - (1)                                                                    Titanium   0.40   0.40   0.40  0.40 0.40 0.40 0.40                            dioxide                                                                       Saccharin acid                                                                           --     --     --    --   --   --   --                              Sodium saccha-                                                                           0.18   0.18   0.18  0.18 0.18 0.18 0.18                            rin                                                                           Sodium mono-                                                                             0.76   0.76   0.76  0.76 --   --   --                              fluorophos-                                                                   phate                                                                         Sodium fluoride                                                                          --     --     --    0.10 0.22 0.33 --                              % soluble  --     --     10.4  12.6 5.25 --   --                              fluoride (2)                                                                  Water      44.16  46.16  42.16 42.16                                                                              42.7 42.59                                                                              42.92                           Sodium alumino-                                                                          22.00  20.00  24.00 24.00                                                                              24.00                                                                              24.00                                                                              24.00                           silicate (SAS)                                                                SAS type   ← ← Zeolex 25 SP                                                                           →                                                                           →                                                                           →                          pH of SAS  ← ← ← 6.7 →                                                                    →                                                                           →                                                                           →                          Calcined   --     --     --    --   --   --   --                              alumina                                                                       Sodium lauryl                                                                            1.50   1.50   1.50  1.50 1.50 1.50 1.50                            sulphate -                                                                    Water      4.00   4.00   4.00  4.00 4.00 4.00 4.00                            Berol 513 Phos-                                                                          --     --     --    --   --   --   --                              phate ester                                                                   (sodium salt)                                                                 Phosphoric acid                                                                          --     --     --    --   --   --   --                              (80-90% aq. soln.)                                                            Flavour    1.00   1.00   1.00  1.00 1.00 1.00 1.00                            Chloroform --     --     --    --   --   --   --                              pH of denti-                                                                             7.0    7.0    7.0   7.6  7.6  7.1  6.8                             frice - (3)                                                                   ______________________________________                                    

                  TABLE 1B                                                        ______________________________________                                                  Example                                                             Component   8      9       10    11   12   13                                 ______________________________________                                        Glycerine   25.00  25.00   25.00 25.00                                                                              25.00                                                                              25.00                              Sodium carboxy-                                                                           1.05   1.10    1.10  1.10 1.10 1.05                               methyl cellu-                                                                 lose - (1)                                                                    Titanium    0.40   0.40    0.40  0.40 0.40 0.40                               dioxide                                                                       Saccharin acid                                                                            --     --      --    --   --   0.12                               Sodium saccha-                                                                            0.18   0.18    0.18  0.18 0.18 --                                 rin                                                                           Sodium mono-                                                                              0.76   0.76    0.76  0.76 0.76 0.76                               fluorophos-                                                                   phate                                                                         Sodium fluoride                                                                           --     --      --    --   --   --                                 % soluble   --     10.4    9.95  9.95 --   --                                 fluoride (2)                                                                  Water       42.74  35.69   38.19 40.69                                                                              39.11                                                                              36.6                               Sodium alumino-                                                                           17.00  20.00   17.50 15.00                                                                              17.00                                                                              17.00                              silicate (SAS)                                                                SAS type    ← Zeolex 25 SP                                                                              →                                                                           →                                                                           →                             pH of SAS   ← ← 6.7 →                                                                       →                                                                           →                                                                           →                             Calcined    10.00  10.00   10.00 10.00                                                                              10.00                                                                              10.00                              alumina                                                                       Sodium lauryl                                                                             1.77   1.77    1.77  1.77 1.55 1.77                               sulphate -                                                                    Water       --     4.00    4.00  4.00 4.00 4.00                               Berol 513 Phos-                                                                           --     --      --    --   --   1.50                               phate ester                                                                   (sodium salt)                                                                 Phosphoric acid                                                                           --     --      --    --   --   --                                 (80-90% aq. soln.)                                                            Flavour     1.10   1.10    1.10  1.10 0.90 1.3                                Chloroform  --     --      --    --   --   0.50                               pH of denti-                                                                              --     6.8     7.2   7.3  7.5  6.4                                frice - (3)                                                                   ______________________________________                                    

                  TABLE 1C                                                        ______________________________________                                                  Example                                                             Component   14     15     16    17    18   19                                 ______________________________________                                        Glycerine   25.00  25.00  25.00 25.00 25.00                                                                              25.00                              Sodium carboxy-                                                                           1.05   1.05   1.05  1.05  1.05 1.05                               methyl cellu-                                                                 lose - (1)                                                                    Titanium    0.40   0.40   0.40  0.40  0.40 0.40                               dioxide                                                                       Saccharin acid                                                                            0.12   0.12   0.12  0.12  0.12 0.12                               Sodium saccha-                                                                            --     --     --    --    --   --                                 rin                                                                           Sodium mono-                                                                              0.76   0.76   0.76  0.76  0.76 0.76                               fluorophos-                                                                   phate                                                                         Sodium fluoride                                                                           --     --     --    --    --   --                                 % soluble   --     --     --    --    --   --                                 fluoride (2)                                                                  Water       36.1   38.1   36.9  36.4  38.4 35.1                               Sodium alumino-                                                                           17.00  17.00  17.00 17.0  17.0 17.0                               silicate (SAS)                                                                SAS type    ← ← Zeolex 25 SP                                                                            →                                                                           →                             pH of SAS   ← ← ← 6.7 →                                                                     →                                                                           →                             Calcined    10.00  10.00  10.00 10.00 10.00                                                                              10.00                              alumina                                                                       Sodium lauryl                                                                             1.77   1.77   1.77  1.77  1.77 1.77                               sulphate -                                                                    Water       4.00   4.00   4.00  4.00  4.00 4.00                               Berol 513 Phos-                                                                           1.50   --     1.50  1.50  --   --                                 phate ester                                                                   (sodium salt)                                                                 Phosphoric acid                                                                           0.50   --     --    0.50  0.50 --                                 (80-90% aq. soln.)                                                            Flavour     1.3    1.3    1.3   1.3   1.3  1.3                                Chloroform  0.50   0.50   0.20  0.20  0.20 3.5                                pH of denti-                                                                              5.5    6.7    6.3   5.5   6.6  7.4                                frice - (3)                                                                   ______________________________________                                    

The dentifrice formulations of Examples 1 to 4, 8 to 14, 16 and 17 allaged well in the unlined aluminium tubes over a three month period at43° C. though Example 11 (containing only 15% of SAS) showed separationand some tarnishing of the tube.

The formulations of Examples 5 to 7, 15, 18 and 19 all resulted ingassing when held at 43° C. for 3 months.

The Zeolex 25 SP SAS material is described by the manufacturer as havingthe following characteristics:

Formula: 1 Na₂ O . 1 Al₂ O₃ . 14 SiO₂.nH₂ O

Texture: a fine powder free from hard particles

Particle size: 99.5% passes through a 325 mesh (U.S. sieve sizes) screenwhich has mesh openings of 44 microns.

Moisture loss: approx. 7% on heating to 105° C.

Loss on ignition: not more than 15% at 1000° C.

Apparent density: 0.3 to 0.4 g/ml

Total aluminium as Al: 4 to 5%

Total silica as SiO₂ : 70 to 75%

Sulphate as SO₄ ²⁻ : not more than 1.5%

Chloride as Cl⁻ : not more than 0.05%

Heavy metals as Pb: not more than 20 ppm

Lead as Pb: not more than 5 ppm

Arsenic as As: not more than 5 ppm

The material has a stirred slurry pH of 6.7.

Other BEROL anionic phosphate esters may replace BEROL 513 withcorresponding results.

We claim:
 1. A stable dentifrice contained in an unlined aluminium tubeconsisting essentially of an aqueous dentally acceptable oral vehicle,at least 27.5% by weight of the dentifrice comprising water anddispersed in the said oral vehicle from 10 to 40% by weight of thedentifrice of a neutral sodium aluminosilicate polishing agentcontaining about 4-5% total aluminium as Al and having a stirred slurrypH in the range from 6.5 to 7.5, and a stabilizing amount ofmonofluorophosphate ion, the dentifrice having a stirred slurry pH inthe range from 5.5 to 8, said monofluorophosphate ion stabilizing saiddentifrice against gas generating reaction between the components ofsaid dentifrice when said dentifice is in contact with the surface ofsaid unlined aluminium tube.
 2. A dentifrice as claimed in Claim 1 inwhich the dentifrice comprises at least 30% by weight of water.
 3. Adentifrice as claimed in Claim 2 in which the dentifrice comprises 35and 60% by weight of water.
 4. A dentifrice as claimed in Claim 3 inwhich the dentifrice comprises 39.69 to 55% by weight of water.
 5. Adentifrice as claimed in Claim 1 in which the polishing agent comprises10 to 30% by weight of the dentifrice.
 6. A dentifrice as claimed inClaim 5 in which the siliceous agent comprises 15 to 25% by weight ofthe dentifrice.
 7. A dentifrice as claimed in Claim 1 in which thestirred slurry pH of the polishing agent is in the range 6.5 to 7.5. 8.A dentifrice as claimed in Claim 7 in which the stirred slurry pH of thepolishing agent is in the range 6.7 to 7.3.
 9. A dentifrice as claimedin Claim 1 comprising at least 0.01% of monofluorophosphate ion.
 10. Adentifrice as claimed in Claim 9 comprising at least 0.05% ofmonofluorophosphate ion.
 11. A dentifrice as claimed in Claim 10comprising at least 0.09% of monofluorophosphate ion.
 12. A dentifricecontained in an unlined aluminium tube consisting essentially of 35% to50% by weight water, 0% to 30% by weight of glycerine, 15 to 25% ofsodium aluminosilicate polishing agent containing about 4-5% totalaluminium as Al and having a stirred slurry pH in the range 6.5 to 7.5,at least 0.5% by weight of alkali metal monofluorophosphate, calcinedalumina in an amount in the range 0% to 15% by weight and one or moreorganic surface active agents in an amount not in excess of 5% byweight, the dentifrice having a stirred slurry pH in the range 5.5 to 8,said monofluorophosphate ion stabilizing said dentifrice against gasgenerating reaction between the components of said dentifrice when saiddentifrice is in contact with the surface of said unlined aluminiumtube.